The light color of a traditional light source such as an incandescent light source or a fluorescent light source falls into a predetermined spectral range, and the light color of a single light source cannot be randomly adjusted. To achieve an organic light emitting display device with adjustable color, a large quantity of the light sources must be assembled and the light intensity of these light sources must be controlled. However, the achieved organic light emitting display device with adjustable color has the disadvantages of low working efficiency, huge size, non-uniform spatial distribution of light color and the like.
On the other hand, an organic light emitting diode (referred to as OLED) has the advantages of autonomous light emission, wide viewing angle, quick response, high luminous efficiency, low working voltage, simple manufacturing procedure, low cost and the like. The basic working principle of the OLED is as follows: under the action of an electric field, electrons are injected from a cathode, holes are injected from an anode, the injected electrons and holes are transmitted in an organic layer and are radiatively recombined in a luminous layer to emit photons. Like a general diode, the organic light emitting diode has unidirectional conduction characteristics of forward conduction and reverse cut-off.
In the prior art, a single OLED has nonadjustable light color, and only has one light color; the OLED is driven in a direct-current driving manner, and in this way, the whole structure of the single OLED is lightened within a cycle, namely the whole structure is in a luminous state, so that the service life of the OLED is shortened.